Diagnostic and evaluation method for structures based on ambient microtremors

Abstract

To provide a microtremor-based structure diagnostic evaluation method that is different from a conventional method of performing a diagnostic evaluation of safe and soundness of a structure as well as safety thereof by directly applying external force and the like to an object, and can perform a diagnostic evaluation of earthquake proof of the structure, as well as safe and soundness thereof, and an effect of a countermeasure work and reinforcement work thereof at low costs and quickly.SOLUTION: A method for evaluating a performance of a structure due to a microtremor observation is configured to: observe a microtremor observation history at a plurality of observation points within the structure; calculate an estimation value of an index to be used in an earthquake proof design of the structure, using a root mean square (RMS) of these time histories; and perform an evaluation of an earthquake proof performance on the basis of the observation of the structure, using a ratio of the value to be used at a time of designing to the value of the index.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] This invention relates to the seismic resistance, structural integrity, and countermeasures / reinforcement measures of a structure based on its constant micro-vibrations. This technology concerns a method for diagnosing and evaluating the effectiveness of structures. [Background technology]

[0002] From the human body, machines, and buildings to cliffs, the ground, and trees, to various things around us Diagnosing and evaluating performance is fundamental to living a safe and comfortable life, and many devices... The technology is already in practical use. Among these, the seismic resistance and structural integrity of buildings, infrastructure facilities, and other structures are being improved. Diagnosing and evaluating all sexes presents the following difficulties: over long periods, under various natural environmental conditions. They are. Each one has a different shape and material. Destructive testing is not possible. It exceeds the scale of human beings. Movement is difficult. It cannot be fully described in documents or data. No. Structures are supported by the ground, and the properties of the ground are more complex than those of man-made structures visible above ground. Therefore, there is a high degree of uncertainty regarding the timing, magnitude, and vibration characteristics of sudden external forces such as earthquakes. stomach.

[0003] Furthermore, the conventional method for evaluating the seismic resistance of existing buildings is to calculate the structural seismic index (Is value). Although this is being done, experts judge information such as drawings and input it into a computer program. The complex calculations required significant expense and time. Furthermore, the calculation method was not unique. Because there were inputs based on branching and judgment, it was considered that subjective elements were likely to be introduced as a result, third The system of judgment meetings by relevant organizations has been institutionalized. In other words, the above conventional methods are costly. It was a process that required considerable effort and time.

[0004] Diagnostic and evaluation methods for entire structures that have been put into practical use to date include a) drawings and calculations a) Checking consistency with the document, b) Recalculating the structure, c) Calculating using a different calculation method d) devices that apply vibration using a vibrator to measure the shaking, e) check sheet There are methods that assign scores and compile data in a T-form, and f) methods based on microtremor observations. New construction inspections include: a) or b) Seismic diagnosis falls under the category of c). However, the calculations listed in a) to c) The method using calculations involves extracting the numerical basis from drawings, etc., so the actual structure and Whether the support conditions are as described is an assumption. Also, inside the structure Even if detailed calculations are performed and a 100% accurate determination can be made, the foundation and surrounding ground conditions... The calculation results will be largely determined by the specifics. Also, if you use the vibrator listed in d), The method is also flawed because the energy of the vibrator is too small compared to the potential energy of the structure and the surrounding ground. As with structural calculations, this cannot be considered a highly accurate assessment.

[0005] Constant tremors provide far more comprehensive, detailed, and voluminous information compared to the information on which the above methods rely. It includes information on the structure and the surrounding ground. While the amplitude of normal tremors is only a few microns, Although small, the enormous mass of the structure and surrounding ground is constantly vibrating, resulting in a large amount of energy. It has that. Spatially, it vibrates at all points of the structure and the surrounding ground, and the amount of information is The amount of information is incomparably greater than that found in design documents or information about the vibration generator. In particular, the risk of a major earthquake In evaluating this, it is important to be able to measure actual vibrations with the ground as the input source, similar to earthquakes. .

[0006] Conventionally, methods for diagnosing structures using constant micro-vibrations have been used, for example, the technology disclosed in Patent Document 1. Several attempts have been made to achieve this. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 3876247 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, conventional techniques do not allow for the visual identification of periods that appear to be superior from the Fourier spectrum. This method involves determining and discussing the changes, and extracting only a small portion of the abundant information contained in constant, minute movements. It was merely something to produce. Therefore, the diagnostic results were insufficient in both accuracy and content, and the structure It failed to establish itself as a diagnostic method. Furthermore, the prior art, including Patent Document 1, Because the calculated index was not an index used in the current design standards or seismic diagnosis standards, It could not be applied to evaluation or diagnosis within the framework of row criteria. Furthermore, the design of the current standards The indicators do not directly evaluate the continued usability of structures. However, the seismic resistance of current structures is... In this specification, the design standards and seismic diagnosis standards are collectively referred to as the current standards. The standard is simply called the diagnostic standard, and the seismic design standard is simply called the design standard.

[0009] Furthermore, the distribution coefficient of story shear force in the height direction, the ultimate horizontal bearing capacity, and the current seismic design are used in the current seismic design. The product of the cumulative strength index and shape index used in seismic diagnosis is not something that can be measured directly. The current standards do not specify the assumed seismic motion, and furthermore, the current calculation method is There was also the problem of inputs being based on branching or judgment rather than intentionality.

[0010] In view of the problems found in the prior art, including the above-mentioned Patent Document 1, the present invention addresses the constant micro-vibrations The information is used in the current diagnosis and seismic retrofitting design of existing structures, specifically the cumulative strength index and structural seismic index. Expected values ​​of the standard, and expected values ​​of the distribution coefficient of story shear force in the height direction used in current new construction designs. Alternatively, the aforementioned indicators and damage assessments can be linked to the degree of damage in order to directly evaluate the continued usability of the structure. By directly obtaining constant values ​​from microtremor measurements, information about actual structures and surrounding ground systems can be obtained. The objective is to provide a new method for extracting and using this information in the design, diagnosis, and evaluation of structures. The method of the present invention is for microtremor diagnosis (MTD). It is called that. [Means for solving the problem]

[0011] This invention was made to solve the above problems, and its structural features include constant micro-vibration. In a method for evaluating the performance of a structure by observation, simultaneous observation at multiple observation points within the structure We observe the time history of minute tremors at all times, and use the mean square root (RMS) of these time histories to determine the previous The estimated values ​​of the indicators used in the seismic design of the structure are calculated, and these values ​​are used at the design stage. The seismic performance of the structure based on the aforementioned observations is evaluated using the ratio to the index value. It is located there.

[0012] Furthermore, the continuously measured constant micro-motion time history is divided, and multiple partial time histories are extracted, each The expected value of the index is calculated with respect to a partial time history, and its sample mean is used as the estimated value of the index. This is possible. In this case, the duration of the partial time history shall be 1 to 2 minutes. That is preferable.

[0013] In this invention, the observations are performed after the construction of a new structure, before and after renovation work, and during periodic diagnostics. By performing this procedure and comparing the estimated values ​​at each observation point, the seismic performance of the structure and the ground can be assessed. At least one of the following: the risk of collapse during an earthquake, the change over time in usability, and the changes before and after renovation work. It may also be a diagnostic and evaluation tool for determining which of the two is correct.

[0014] In the present invention, the index is the distribution coefficient in the height direction of story shear force as defined in the current standards and The lateral load-bearing capacity can be set to the level specified in the current standards.

[0015] Furthermore, in the present invention, the index is the base shear coefficient as defined in the current standards and the current standards A specified acceleration response magnification can also be used.

[0016] Furthermore, in the present invention, the index is a cumulative strength index and a shape index as defined in the current standards. It may also be the product of these factors, or a newly defined degree of damage or risk of falling as described in this invention. [Effects of the Invention]

[0017] According to the present invention, the cumulative strength index currently used for diagnosing and seismically retrofitting existing structures, Expected values ​​of structural seismic resistance index and the distribution of story shear force in the height direction used in current new construction designs Expected values ​​of the number of injuries and newly defined damage estimates for directly evaluating the continued usability of structures. By directly obtaining these values ​​from micro-tremor measurements, vertical arrays were created for each part of the structure. Observation allows for the measurement of vibration characteristics, intensity, and degree of damage in each section (zone) of the floor. As a result, earthquake resistance, structural integrity, and repairs can be carried out in far greater detail, quickly, and inexpensively than with conventional methods. This allowed us to evaluate the effectiveness of the design.

[0018] In other words, according to the present invention, by using the above indicators, it is possible to determine the value after new construction, after renovation work, and fixed At the time of diagnosis, diagnostic evaluation can be performed much more cheaply and quickly than current diagnostic assessment or testing methods. Since it is possible to perform evaluations or inspections, rational seismic reinforcement design and seismic reinforcement of new structures can be implemented. This will allow us to perform the calculation. [Brief explanation of the drawing]

[0019] [Figure 1] An explanatory diagram showing an example configuration of a diagnostic system to which the method of the present invention is applied. [Figure 2] A flowchart illustrating the basic processing procedure between the microtremometer and the analyzer. [Figure 3] An explanatory diagram showing the factors necessary for calculating the structural seismic index, the ultimate horizontal load-bearing capacity, and the degree of damage in the method of the present invention. [Figure 4] A flowchart illustrating the overall processing steps of the present invention. [Figure 5] A diagram illustrating the routine processing steps performed within the analyzer. [Figure 6] This is a schematic diagram illustrating the actual effects and seismic forces of an earthquake. (a) shows the actual effects, (b) shows the spring-mass system, and (c) shows the seismic forces. [Figure 7] Figure 6(b) shows a model (single-mass system) where multiple point masses and a spring are combined into one, as depicted by black dots and lines. [Figure 8] A graph showing the relationship between bilinear cumulative strength index and inter-story drift angle. [Figure 9] A graph showing the relationship between frictional inter-story shear force and support section acceleration. [Figure 10] A graph showing the relationship between frictional inter-layment shear force and inter-layment velocity. [Figure 11] A graph showing the relationship between frictional inter-story shear force and inter-story displacement. [Figure 12] A diagram illustrating the placement of four types of microtremometers on the first floor of a four-story hospital. [Figure 13] This diagram shows the layout of four types of microtremometers on the second floor of a four-story hospital, using the same building as an example. [Figure 14] This diagram shows the layout of four types of microtremometers on the third floor, using a four-story hospital as an example. [Figure 15] This diagram shows the arrangement of four types of microtremometers on the fourth floor, using a four-story hospital as an example. [Figure 16] Layout plan of columns and walls on the first floor and beams on the second floor of Y Hospital. [Figure 17] Layout plan of columns and walls on the second floor and beams on the third floor of Y Hospital. [Figure 18] Assembly diagram of Y Hospital, X direction, 1-way axis. [Figure 19] Drawing of two axes in the X direction at Y Hospital. [Figure 20] Assembly diagram of four axes in the X direction at Y Hospital. [Figure 21] Assembly diagram of the A-axis in the Y direction at Y Hospital. [Figure 22] Drawing of the axis structure of Y Hospital, direction Y, through path B. [Figure 23] A panoramic view of the building for Example 2. [Figure 24] Figure 23 shows the installation status of the A2 measuring instrument on the first floor, corresponding to Figure 25. [Figure 25] An explanatory diagram showing the placement of measuring instruments and reinforcement locations, corresponding to Figure 24. [Figure 26] Micro-displacement trajectories for each floor. [Figure 27] Animation of vibrations on the roof of an 11-story SRC building, measured before reinforcement. [Figure 28] An animation of the vibration of the rooftop of an 11-story SRC building after reinforcement. This figure shows a single moment in the visualization (animation) of the movement of the reinforced rooftop surface, obtained by inputting displacement data (XYZ 3 components) from microtremometers installed at three locations on the rooftop surface into structural analysis result visualization software. [Figure 29] A schematic diagram showing the arrangement of the block wall, foundation, ground, and microtremor sensor. [Figure 30] An explanatory diagram showing the overall view of a concrete block wall in different situations, labeled (a) to (c). [Figure 31] Diagram showing the placement of microtremors on the concrete block wall and at the reference point. [Modes for carrying out the invention]

[0020] The ground surrounding a structure is constantly experiencing minute vibrations. The source of this vibrational energy is tides. These include traffic vibrations, etc. The amplitude is several microns [10 = -6 It is approximately m. The constant tremors observed (hereinafter also simply referred to as "tremors") are caused by tremors in the surrounding ground that are affecting the foundation. This is the result of the signal entering the structure and being amplified or attenuated as it propagates within the structure.

[0021] Constant microtremors are observed using microtremometers (accelerometers) installed inside the structure. This is the absolute acceleration at a specific point, and is usually divided into three orthogonal components: a vertical component and two horizontal components. Each is measured. Because the amplitude is small and the duration is short, the structure is a steady-state linear system. Yes, constant tremors are a stationary stochastic process. It can be treated mathematically as a part of the process.

[0022] Hereinafter, embodiments of the present invention will be described based on the drawings. Figure 1 shows the application of the method of the present invention. This is an explanatory diagram showing an example of the configuration of a diagnostic system. According to the diagram, the overall diagnostic system is: Micromotors 1 are placed at the layer boundaries 10a, 10b, and 10c of each layer of the structure 10, and the micromotors Based on the data recorded by 1, various vibration characteristic indices and various seismic resistance standards used in current standards An analyzer (e.g., a personal computer) 2 that calculates a sex evaluation index and a new evaluation index, It is composed of.

[0023] Of these, the micro-motion sensor (for example, the JU410 micro-motion sensor manufactured by Hakusan Kogyo) 1 is an acceleration sensor It has built-in memory and GPS. Furthermore, analyzer 2 is equipped with micro-motion diagnostic software. The data recorded by the microtremometer 1 can be received via USB, LAN, or the internet. Then, the calculations of the present invention method, which are described in detail below, are performed, and various vibration characteristic indices and those used in current standards are obtained. It calculates various seismic resistance evaluation indices and new evaluation indices. In addition, analyzer 2 analyzes a certain layer. For example, the micro-displacement data acquired by the micro-motion sensors 1 installed in three locations is stored in the analyzer 2. The data is sent to visualization software, where the surface movement is animated in 3D, and then analyzer 2 is equipped The vibration of the structure 10 is displayed on a display device (not shown). Alternatively, the vibration mode is displayed and visualized so that it can be easily seen and confirmed at a glance.

[0024] The outline of the present invention method will be described below with reference to Figures 2 to 5. Figure 2 shows the microtremometer 1 and analyzer. This is a flowchart showing the basic processing steps that take place between step 2 and step 2. According to the diagram, Motion meter 1 measures and records ambient tremors (the time history of acceleration at observation points and reference points on the layer boundary). The analyzer 2 filters the received measurement record data in the frequency domain, and then processes it. The acceleration time history in the frequency band near the natural frequency of the structure is obtained. After that, the time domain is divided into parts of about 2 minutes, and for each part, the time history of interest is examined. The energy transfer coefficient and various indicators are calculated. After calculation, the vibration characteristic indicators for each part are calculated. The average value and standard deviation of the seismic performance index and seismic damping performance index are calculated, and the average value is used for each index. The process is performed to obtain an estimated value.

[0025] Furthermore, according to Figure 3, the magnitude of the assumed seismic motion in the present invention method is the maximum acceleration, maximum velocity The intensity is expressed in degrees, maximum displacement, and duration of strong earthquake. Microtremors are also used on each floor of the target structure. And they are installed in a vertical array on the reference surface. Furthermore, the performance of the target layer of the target structure is required to meet the necessary requirements. It is expressed in terms of horizontal load-bearing capacity, ductility index, aging index, and limit cycle count. And micro-vibrations After the instrument has been set up, follow the procedure shown in Figure 2 to perform microtremor measurement and analysis using the microtremor meter 1. The measurement results using method 2 were analyzed, and the vibration characteristic index (central period, height direction of story shear force) was determined. (Coefficient indicating the fabric) and seismic performance evaluation index (horizontal load-bearing capacity, ultimate cumulative strength index and shape index) The product of the above and seismic absorption evaluation index (historical absorbed energy, degree of damage) are calculated. The final step is to calculate the structural seismic index, the ratio of horizontal load-bearing capacity, and the degree of damage, and then complete the process.

[0026] Figure 4 is a flowchart showing the overall processing steps of the method of the present invention. According to this figure, First, a preliminary survey of the target structure will be conducted. Specifically, this will include design drawings, calculations, renovation history, and damage records. We will collect historical records, past seismic assessments, and other literature, and conduct on-site surveys to install microtremor meters. Determine the possible locations. Next, as part of the microtremor measurement plan, determine the measurement time period, measurement duration, and microtremor meter (instrument). Determine the placement and reference plane of the instruments. After formulating the microtremor measurement plan, the instrument isolation will be used to implement the microtremor measurement. Time synchronization, micro-motion measurement, and data recording are performed, and analysis is carried out, including time history calculations and vibration characteristics. Performance and behavioral indicators are calculated. After the above is completed, the diagnosis is performed. In this case, For diagnoses in accordance with current standards, structural seismic index or seismic resistance ratio is used, and seismic performance The degree of damage is used in the evaluation.

[0027] Figure 5 is an explanatory diagram showing the processing procedures performed within analyzer 2, broken down by routine. According to this figure... For input data, in addition to the data for each assumed seismic motion parameter, the observed microtremor time history and observation data are also included. Measurement time, observation frequency band, analysis time, and analysis frequency band are included, and each data is an attribute of the observation point. Then, various data points as structural specifications are entered.

[0028] The calculation routine includes: calculation of the time history of the microtremor of interest, part division, calculation of vibration characteristic index, Performance metrics are calculated. The preliminary calculation routines include FFT, filtering, and zero point calculation. Correction, mean square calculation, central frequency calculation, and bandwidth index calculation are performed.

[0029] The display routine displays input data, observation time history, spectrum, central frequency, and In addition to displaying the vibration amplitude index, vibration characteristic index, and performance index, it also displays the time history and power Spectral display, trajectory display, and surface motion animation display are also performed. Output / transfer routing In this context, communication is conducted via paper, hardware devices, USB, LAN, radio waves, etc.

[0030] The outline of the present invention method has been described above based on Figures 1 to 5, but below the present invention method will be described in more detail. The present invention will be explained in detail. (MTD: Micro Tremor Diagnosis) ) In this case, the root mean square (RMS) of the duration, displacement, velocity, and acceleration time history of microtremors. ), peak factor, zero-crossing period, central period, bandwidth index, and also the microtremor of the reference point. Microtremors and structures using the energy transfer coefficient between the time histories of displacement, velocity, and acceleration and the time history of the microtremor of interest. This involves quantitatively analyzing the vibration characteristics of an object. This is done by characterizing stochastic processes using the second moment of inertia. This is a correlation analysis between input and output.

[0031] Furthermore, in microtremor measurement, from the continuous measurement duration for one microtremor meter configuration, Several sets of time histories are extracted, and for each set, the following quantities are calculated to obtain the sample mean and target value. Calculate the quasi-deviation. For seismic performance evaluation, use the sample mean of each quantity as an estimate of the expected value of each quantity. Use.

[0032] Figure 6 is a schematic diagram showing the actual effects and seismic forces of an earthquake, with (a) being an actual effect. (b) shows the spring / mass point meter, and (c) shows the seismic force. Microtremor diagnosis is performed by drawing the structure's ground system. As shown in 6(a) to (c), the surrounding ground 21 is modeled as a rigid floor, and the structure 10 as a point mass and spring. The calculation is performed using a quantified model. This is the same as the current seismic standards.

[0033] The ground is constantly subjected to tides, traffic vibrations, etc., and is several microns thick. [10 -6 Vibration with a tiny amplitude of approximately m This is causing motion. This is called microtremor. Figure 6( The same applies to the surrounding ground 21 of the structure 10, which is represented by a solid rectangle in a). Micro-movements are caused by the foundation. Since the particles enter the creation 10 and propagate through the interior of the structure 10, the structure 10 is constantly experiencing slight vibrations. Because they have been subjected to random inputs for a sufficiently long period of time, both the surrounding ground 21 and the structure 10 have their own unique properties. It is thought to be vibrating in vibration mode.

[0034] By installing multiple micro-motion meters (accelerometers) 1 inside the structure 10 as shown in Figure 1, micro-motion The time history can be observed. For example, as shown in Figure 6(b), each layer of structure 10 can be measured as a point mass. And to correspond to modeling with springs, one unit is installed in a vertical array at a representative point of each layer. The structure 10 is placed in a steady linear state because the amplitude of the micro-vibration is minute, and within a finite duration the structure 10 is in a steady linear state. It is a stem, and constant tremors are stationary stochastic processes. It can be treated mathematically as a part of the c Process.

[0035] Earthquake ground motion is caused by displacement resulting from the rupture of bedrock and ground in the epicenter region, which then acts as waves in the ground surrounding structures. Since this is a phenomenon where something reaches a certain point and causes it to vibrate, the source of vibrational energy is different from that of constant micro-tremors. Within a narrow area, it is thought that both the surrounding ground and structures vibrate in their natural modes, resulting in constant micro-vibrations. It is thought to vibrate in the same way as [another entity]. Based on the above, the following indicators can be calculated from microtremor observations to determine the dynamic properties of the structure and earthquakes. We predict and calculate the behavior over time and calculate the current seismic performance evaluation index and new evaluation index.

[0036] 1. Central Period (Vibration Characteristic Index, Part 1) The central period T of micro-displacement in a certain direction at a certain point within a structure. c [sec] is calculated as follows: .

[0037]

number

[0038]

number

[0039] However, ω cy [rad / sec] is the RMS of the time history obtained by differentiating an arbitrary minute time history. The central frequency is calculated by dividing it by its own RMS (the "center" here refers to the English word "centr This is what was used when "al frequency" was translated into Japanese as "central". It doesn't mean it's specifically at the center of something, but rather it's the expected value of the zero-crossing frequency, and This refers to the frequency that plays a central role in discussing the frequency characteristics of time history in the theory of regular oscillations. ) and a (see column a in Table 1) and b (see column b in Table 1) are the displacement time, respectively. This is the RMS of the history and speed-time history.

[0040] [Table 1]

[0041]

number

[0042] Here, [0, t0] is the duration of the micro-motion time history. Velocity, acceleration, and rotation angle. The central period can be similarly defined for the same elements. The central period of the time history obtained from multiple microtremors installed in a certain part of the structure is measured. By calculating and comparing them, we can determine whether that part is vibrating in its own specific vibration mode. It is possible.

[0043] 2. Expected value of the coefficient representing the distribution of story shear force in the height direction (Vibration characteristic index, part 2) Current seismic standards and seismic diagnosis standards for buildings are based on the mechanical model shown in Figure 6(b). , seismic force acting on the jth floor of the building (P j ) seismic intensity (k j ) and the weight of that layer (w j ) and It is represented in this way.

[0044]

number

[0045] From the above relationship, when a building consisting of n layers vibrates due to the effects of an earthquake, the i-th layer The maximum shear force is called the layer shear force a (see column a in Table 2), and the weight b supported by that layer is... (See column b in Table 2) and the seismic story shear force coefficient (C i It is given as the product of ).

[0046] [Table 2]

[0047]

Number

[0048] Furthermore, the seismic layer shear force coefficient (C i ) is defined as the product of the regional coefficient (Z), the vibration characteristic coefficient (R t ), the standard shear force coefficient (C0), and the coefficient (A ) representing the distribution of the layer shear force in the height direction. Note that in the primary design assuming small and medium earthquakes, C0 = 0.2, and in the secondary design for large earthquakes, it is determined to use C0 = 1.0. i

[0049]

Number

[0050] Note that for the first layer,

[0051]

Number

[0055] Using the above relationship, the absolute acceleration energy transfer coefficient in the k-direction of the i-th layer obtained from microtremor diagnosis Assuming that a (see column a in Table 4) is also preserved during the elastic response due to seismic motion input, and Then, multiply by the maximum acceleration at the reference point to calculate the expected value b of the maximum absolute acceleration (see column b in Table 4). And the mass m of each layer of the structure j Therefore, the expected value of the maximum story shear force is c (see column c in Table 4). We find the expected value E[A] of the coefficient that represents the distribution of the shear force in the height direction in the k direction of the i-th layer. ik ] of It can be obtained (Equation 9). However, the maximum acceleration of the aforementioned reference point is the denominator of the rightmost side of Equation 9. It is not displayed because it is omitted as it is received by the child. Also, the absolute acceleration energy transfer coefficient a (Table 4) (See column a) means that in the energy transfer coefficient as defined in paragraph "0067" of this specification, The micro-motion time history of interest is defined as the absolute acceleration time history, that is, the absolute acceleration time in the k direction of the i-th layer. This is the ratio of the RMS of the time history to the RMS of the absolute acceleration time history in the k-direction of the first layer. Also, Equation 9 The second equality sign from the right is the equation of motion for the mechanical model of the structure in Figure 6(b) (paragraph) This is derived from (see "0032" to "0034"). Also, the last equality sign in number 9 is from paragraph "0 The assumption described in "021", namely the absolute acceleration time of each layer (layer i) obtained from ambient microtremor observations Under the assumption that history can be mathematically treated as a part of a stationary stochastic process, The expected value of the maximum value within the duration can be calculated by multiplying the RMS by the peak factor. Based on the finding that the peak factors of the absolute acceleration time history of each layer are equal to each other, It is placed there. As shown above, the method of the present invention minimizes the forces acting within a structure during an earthquake. Based on the above assumptions, the current standard design indicators, which are defined using large values, are applied to microtremor observations. Therefore, estimation is performed using the RMS of the absolute acceleration time history of each layer obtained. This method yields a less variable (more stable) maximum value compared to the method that uses the actual measured maximum value. This is to obtain an estimated value, that is, an estimated value of the design indicator.

[0056] [Table 4]

[0057]

number

[0058] Incidentally, in seismic standards, based on various analyses and considerations, the α that appears in the two equations above is as follows: i (Normalized weight) and the building's primary natural period T are used as parameters for A i It stipulates that...

[0059]

number

[0060]

number

[0061] However, T[sec] is calculated assuming that λ is the majority of the columns and beams in the building are made of wood or steel. The ratio to the total height of the floors (excluding the basement) h[m] shall be calculated using the following formula. It is being done.

[0062]

number

[0063] The above regulations apply to the maximum load capacity of each floor from low-rise to super-high-rise buildings, which are tower-like structures. It is said that the shear force distribution has been devised to be expressed by a single formula. According to the seismic standards, the above formula is A i Instead of calculating this, we directly apply it to each individual building, as shown in Figure 6. Create model b) and calculate the maximum value of the story shear force using methods such as time history response analysis and A i of It is also permissible to ask.

[0064] 3. Expected values ​​of average transmission coefficient and response magnification (Vibration characteristic index, part 3) In the model in Figure 6(b), when considering the effects of earthquakes on layer i, the layer that supports The RMS or maximum value of the average acceleration, average velocity, etc. of part b (from layer i to layer n) is given. The following indicators are useful.

[0065]

number

[0066]

number

[0067] Here, mj is the mass of the j-th layer, a (see column a in Table 5), and b (see column b in Table 5) are These are the energy transfer coefficients of acceleration and velocity in the k direction of the j-th layer, respectively, and B aik average Velocity energy transfer coefficient, B vik This is called the average kinetic energy transfer coefficient. However, energy The Ghee transmission rate is the ratio of the RMS of the micromotion time history of the point of interest to the micromotion time history of the reference point, and is used in micromotion diagnosis. In this analysis, it is assumed that this is preserved at the time of the maximum elastic response due to seismic motion input, and the peak factor is appropriate. Assuming this is correct, the maximum response in the time history of interest is calculated by multiplying the maximum input value at the reference point by the energy transfer coefficient. Calculate.

[0068] [Table 5]

[0069] For example, using the average acceleration energy transfer coefficient described above, a certain layer i in a structure supports The absolute acceleration time history a of each point (mass dM) in part b k k-direction component A of the spatial mean of (t) k The expected value of the RMS of (t) E[σ Ak ] corresponds to a (see Table 6) of the acceleration time history of the reference point. Therefore, it can be calculated as follows.

[0070] [Table 6]

[0071]

number

[0072]

number

[0073] The expected value A of the coefficient representing the distribution of story shear force in the height direction in Equation 9. imk Defined by equation 13 The average acceleration energy transfer coefficient B aik The following relationship exists between them.

[0074]

number

[0075] That is, A imk This is the average acceleration of the part supported by the part of interest i and the part supported by the first layer. It can be said that this is the ratio of the average acceleration of the entire structure. In equation 13, the average acceleration transfer coefficient B is calculated by setting j=1. aik is the mean absolute acceleration of the structure. (See column a in Table 7) and the ratio of the absolute acceleration of the reference point b (See column b in Table 7), that is, the total acceleration of the structure The acceleration response magnification R when the body is reduced to a single-degree-of-freedom system as shown in Figure 7. amk The expected value .

[0076] [Table 7]

[0077]

number

[0078] Similarly, B with j=1 in equation 14 v1k This is the case when the entire structure is reduced to a single-degree-of-freedom system. This can be said to be the expected value of the speed response multiplier.

[0079]

number

[0080] The current standard uses the standard shear force coefficient in Equation 6, where C0=0 in the primary design assuming a small to medium earthquake. 2. In the secondary design for major earthquakes, the reason for using C0=1.0 is that the assumed ground conditions The maximum acceleration of vibration is 0.07G to 0.08G for small to medium earthquakes and 0.33G to 0.4G for large earthquakes. This is because G was used, and the acceleration response magnification of the short-period building was considered to be 2.5 to 3. .

[0081] 4. Expected value of the lateral load-bearing capacity (Seismic performance index, part 1) According to seismic standards, each floor of the building's structural model must be A i The load is applied by gradually increasing the distributed shear force. , when the i-th layer yields, the layer shear force a acting on the i-th layer (see column a of Table 8) is defined as the retained horizontal bearing capacity b (see column b of Table 8). The relationship between the layer shear force generated in the structure due to the ground microtremor and the acceleration of the reference point can be expressed by the average acceleration transmission rate (B ) defined in paragraphs "0064" to "0080" of this specification. Also, the relationship between the interlayer displacement and the acceleration of the reference point can be expressed using the transmission rate defined in paragraph "0067" of this specification. Using these, when the maximum value of the interlayer displacement of the i-th layer reaches the yield displacement in the case where the structure responds linearly, the expected value of the layer shear force can be calculated. aik ) This can be considered as the expected value c of the retained horizontal bearing capacity (see column c of Table 8) assuming that the layers other than the i-th layer do not yield. The energy transmission rate e (see column e of Table 8) of the k-directional interlayer displacement (e (t)) of the i-th layer with respect to the acceleration d in the k-direction of the reference point (see column d of Table 8) is defined as the ratio of the respective RMSs as follows. If the maximum value of the acceleration of the reference point when the maximum value e of the interlayer displacement reaches the yield displacement e ik is taken as a ikY

[0082]

Table 8

[0083]

Equation

[0084] The maximum value e of the interlayer displacement ikmax reaches the yield displacement e ikY If the maximum value of the acceleration of the reference point at this time is taken as a ikY then

[0085]

Equation

[0086] The expected value a of the maximum value of the layer shear force at this time (refer to column a of Table 9) is the part supported by the i-th layer of the mass b of b (refer to column b of Table 9) multiplied by the expected value A of the maximum value of the average acceleration of this part bkmax can be calculated

[0087]

Table 9

[0088]

Equation

[0089] The maximum acceleration of the reference point and the expected value of the maximum value of the average acceleration of the above part b are related by the average acceleration energy transfer rate B aik using

[0090]

Equation

[0091] From the above

[0092] )]]

Equation

[0093] From Equation 21 and Equation 24

[0094]

Equation

[0095] The expected value C of the layer shear force coefficient when reaching the holding horizontal bearing capacity uikm is obtained by dividing the above formula by the weight supported by that layer using the relationship of Equation 5

[0096] ​

number

[0097] However, the floor height in the k direction of the i-th layer is H 0ik [m], yield deformation angle R Yik [rad], g[ m / sec 2 ] is assumed to be the acceleration due to gravity. Also, the shear strength of the first layer when the horizontal load capacity is reached. The expected value of the shear coefficient, i.e., the expected value of the base shear coefficient C. ui1km This is from the relationship in equation 8. , the above equation is A i This can be obtained by dividing by . This can be done using equations 9, 17, and 19. , acceleration response magnification R amk and the energy transfer coefficient a of inter-story displacement with respect to the acceleration of the reference point (Table) It can be seen that it can be expressed as (see 10).

[0098] [Table 10]

[0099]

number

[0100] The ratio of horizontal load-bearing capacity obtained above is the expected value of the horizontal load-bearing capacity that the seismic standards require to be defined. Calculate by dividing by the horizontal load-bearing capacity.

[0101] 5. Expected value of the product of the ultimate cumulative strength index and the shape index and the structural seismic resistance index (Seismic performance index, part 2) ) According to seismic diagnosis standards, the beam span and girder direction (horizontal) of each floor (each level) of a low-to-medium-rise reinforced concrete building. (2 directions) For each direction, Structural seismic index I s The basic performance index E0 and the shape index S D It is expressed as the product of , and the longitudinal index T.

[0102]

number

[0103] Regarding the basic performance index E0 in the above formula, the strength index in each direction of the individual columns, walls, and beams of each floor ( A detailed formula is provided for calculating the product of C) and the toughness index (F). However, Theoretically, the basic performance index E0 is the product of the strength index and toughness index of that layer (E0 = It is explained as C×F). The toughness index of a layer is the interlaminar deformation of that layer that reaches its ultimate limit. Since this is the corresponding toughness index, we set it to F U This represents the layer reaching its ultimate limit. A coefficient equivalent to the base shear coefficient in the inter-story drift angle (ultimate cumulative strength index) is C TU This is how it is expressed. .

[0104]

number

[0105] From the above relationship,

[0106]

number

[0107] Equation 29 shows that the story shear force a (see column a in Table 11) is proportional to the interstory displacement e, as shown by the line drawn in Figure 8. This is derived assuming that the function OYU is bilinear. In this case, the yield point Y and the final state The story shear force (cumulative strength index) at point U is equal to (C TY =C TU ), yield correlation displacement (e Y This becomes a cumulative strength index for ). However, Figure 8 shows the story shear force a (see column a in Table 11) The weight Σw supported by that layer and the distribution coefficient A of the story shear force in the height direction. i Divide by the cumulative intensity index C T The inter-story displacement e is divided by the floor height H0 to obtain the inter-story drift angle R, which is then plotted. The letter 'i' is omitted.

[0108] [Table 11]

[0109] The interstory displacement-story shear force relationship obtained from microtremor diagnosis is near the origin of the relationship shown in Figure 8. Let's assume this represents the relationship shown in the same figure. In seismic diagnosis standards, the aging index T and the ductility index F U When set to 1.0, the layer for the seismic motion assumed by the standard (design basis ground motion: G0) When the game reaches its end, the I of that layer S The value is specified to be 0.6. Therefore, Correlated displacement energy transfer coefficient h obtained from dynamic diagnosis egi Corresponding to the design basis earthquake ground motion (G0) Multiply by the reference point displacement to get the expected value of the correlation displacement (E[e G0 When calculating ]), this is exactly , yield displacement (e Y =R Y If H0, then the value is 0.6. Therefore, equation 3 0 is F U If we set =1 and T=1,

[0110]

number

[0111] Assuming that the cumulative strength index and the inter-story drift angle (inter-story displacement) are proportional, the k-type of the i-th layer The quantity obtained by multiplying the cumulative intensity index at the end of the process by the shape index ((C TU S D ) ik The expected value of ) is slightly Correlated displacement energy transfer coefficient h obtained from dynamic diagnosis egik It corresponds to the design basis earthquake motion (G0). Reference point displacement x G0

[1978] Multiply by to obtain the correlation displacement (e G0ik ) calculate this and descend Lower displacement (e Yik This is the value obtained by dividing by ) and multiplying the result by 0.6.

[0112]

number

[0113] Now, according to the seismic diagnosis standards, I s The value = 0.6 corresponds to the 1968 Tokachi-oki earthquake, 1 I, a group of buildings that suffered moderate to severe damage in the 1978 Miyagi Prefecture offshore earthquake. s Estimated values ​​of the distribution and earthquakes Regarding the group of buildings that have never experienced damage (I) s The validity of this was verified by comparing the value distributions. In addition, there were the 1978 Izu Oshima offshore earthquake and the 1987 Chiba Prefecture offshore earthquake. The document includes considerations such as those related to the 2011 Great East Japan Earthquake, but also mentions the 1978 incident off the coast of Miyagi Prefecture. Observed seismic motion up to the earthquake and observed seismic motion in the 21st century, exemplified by the 2011 Great East Japan Earthquake, are different. Since the maximum acceleration, velocity, duration, etc. are orders of magnitude different, the seismic motion assumed by the diagnostic criteria is Therefore, we would like to consider this to be the seismic motion up to 1978, when the standards were first established.

[0114] The strongest earthquake records observed in Japan up to 1978 were compiled by the U.S. National Oceanic and Atmospheric Administration (NOAA). It is compiled into a database and made public. Based on the results of statistical analysis of this data, it can be concluded that the seismic motion at that time was generally accurate. Assuming that the expected maximum displacement is approximately 2.5 cm in both horizontal directions, Substitute into equation 32. Also, the yield displacement e in the k direction of the i-th layer in the same equation. Y[m] is the floor height H0[m] and yield deformation angle R Y Expressed in [rad], the ultimate cumulative intensity index and shape are derived from the energy transfer coefficient. We obtain a formula for calculating the expected value of the product of the indicators.

[0115]

number

[0116] From equation 30 and the above equation, the structural seismic index I s This can be calculated from microtremor diagnosis.

[0117]

number

[0118] However, I sm This is the structural seismic index, F, obtained from microtremor diagnosis. U , and T are the ultimate toughness index and This is a long-term indicator.

[0119] 6. Hysteretic Absorbed Energy (Seismic Control Performance Index, Part 1) Nonlinear response calculations, that is, after a certain layer of a structure reaches its yield strength, i.e., with respect to stress. After the nonlinearity is revealed, the design will determine how the structure deforms and moves under the influence of an earthquake. From the information contained in the book or the information that will be contained therein, the calculations can be made about earthquakes. Even if we identify the movement and simplify the structure and ground as shown in Figure 6(b) or Figure 7, it is not easy. There isn't one.

[0120] There are many different models (constitutive laws) for the stresses and strains acting between each layer of a structure after yielding. It is thought that concrete and soil exhibit nonlinearity even with very small strains. Furthermore, the variables used to explain the nonlinearity include not only the interlayer displacement as shown in Figure 8, but also its phase Factors such as velocity, absolute acceleration, and stress and strain in other directions, such as axial force, can be considered. The components that make up the layers, the materials that make them up, and the connection conditions of each component are diverse. Furthermore, there are various methods for reducing it to a single constitutive law. It's impossible to say which is the correct answer.

[0121] In seismic design, there are several representative nonlinear models, and at the member level, While full-scale models are used for analyzing experimental results, the method of applying force to the experimental apparatus and the measurement of displacements, etc., are also important. Even if it complies with the law, it is necessary to verify its effectiveness in the actual effects of earthquakes in three-dimensional space. That's not possible.

[0122] Figure 9 shows the relationship between frictional inter-story shear force and support portion acceleration, and Figure 10 shows the frictional inter-story shear force. Figure 11 shows the relationship between inter-story velocity and frictional inter-story shear force / displacement, respectively. The diagnosis measures the vibration at representative points of each layer of the actual structure, and compares it to the structural model in Figure 6(b). The response characteristics of each layer can be quantified. From these results, as shown in Figures 9 to 11... The expected value of hysteresis absorption energy can be calculated using a friction-type model.

[0123] This model represents the stress in a structure where stones are stacked, as shown in Figures 9 and 10. Thus, when the absolute acceleration of the part supporting the layer exceeds the limiting acceleration, a relative velocity is generated between the layers. Then, a constant shear force acts in the opposite direction to that velocity.

[0124] Starting from zero interstory displacement, the interstory displacement increases in a constant direction until it reaches a certain magnitude. By the way, when a structure deforms so that the inter-story displacement continues to decrease, and it decreases to a certain size... Therefore, if we now plot the relationship with inter-story displacement when the structure deforms in a way that increases, we get Figure 11. This is how it works. In the bilinear shear force-interstory displacement relationship shown in Figure 8, the interstory shear force Figure 9 shows the relationship between shear force and support acceleration. Therefore, the bilinear shear force-layer relationship is shown. Regarding the portion of the inter-displacement relationship where the shear force is constant (line segment YU in Figure 8), the above friction type model You can apply the letter "ru".

[0125] Hysteretic absorption energy W of the i-th layer calculated from the k-direction component ik As shown in the following equation, The upper surface of the i-th layer of the structure moves relative to the lower surface (interlayer displacement e ik ) in relation to causing Work W done by the restoring force (story shear force) a (see column a in Table 12) ik And the increment (Table 12) (See column b) is obtained by integrating with respect to the duration of the vibration t0.

[0126] [Table 12]

[0127]

number

[0128] The spatially average absolute acceleration and mass in the k-direction of the part supported by the i-th layer are given by A, respectively. ik ( If t) and (Σm), then the equation of motion in the k-direction for the part supported by the part of interest is as follows: It will become.

[0129]

number

[0130] Assuming the restoring force has a yield limit strength a (see Table 13), from equation 36, A ikIt was found that (t) also has a limit value, and this limit acceleration A cik Let's assume that.

[0131] [Table 13]

[0132]

number

[0133] Microtremor observations indicate that when a structure responds elastically, that is, when the restoring force does not have a limiting value, Since the spatial average acceleration of the part supported by layer i can be predicted, let this be a (see Table 14). ru.

[0134] [Table 14]

[0135] When the restoring force is of the frictional type and the bottom surface of the layer vibrates with acceleration a (see Table 14), a (see Table 14) If (Illumination) is part of a steady-state Gaussian process of duration s0, then the hysteretic absorption per unit mass Energy W ik The expected value is obtained from the power spectral density function of a (see Table 14). Each parameter and the limit acceleration A ci The theoretical formula expressed by is derived from the theory of disordered vibrations.

[0136]

number

[0137] Here, E[*]: Expected value of * [operator]

[0138] Furthermore, regarding the k-direction of the i-th layer a (See Table 15): Restoring force [N] eik (t): Relative displacement between the top and the bottom [m] A cik : Limiting acceleration [m / sec 2 Σw: Supported weight [N]

[0139]

Table 15

[0140] Also, for the space-averaged elastic response acceleration time history a of the part supported by the i-th floor during an earthquake (see Table 14 ), and for the k-direction component of the velocity time history obtained by integrating this: s0: Duration of strong ground motion [sec] T vik : Central period of the velocity time history [sec] σ aik : RMS of the acceleration time history [m / sec 2 α vik : Bandwidth index of the velocity time history [dimensionless] σ vik : RMS of the velocity time history [m / sec]

[0141] However, the duration of strong ground motion s0 is the duration of the time history t0 having non-stationarity like ground motion (x(t)) is the duration for treating it as the part of the duration s0 of a stationary Gaussian process (G(t)) having the same power spectral density function, and the maximum value of x(t) is such that it appears as the maximum value an average of once during the duration s0 of G(t).

[0142] The above T vik The following parameters are calculated from the time history obtained by microtremor observation, the energy transfer rate, and the predicted value of the maximum value of the vibration time history of the reference point due to the assumed earthquake. First, it is assumed that the structure even during an earthquake, vibrates in the vibration mode obtained by microtremor observation during elastic response, and the vibration period T of a (see column a of Table 16)​​​vik , bandwidth exponent α vik is calculated using the lower surface of the part supported by the i-th layer, i.e., the acceleration time history b of the relative motion at the upper surface of the i-th layer (see column b of Table 16). Furthermore, the RMS σ of c (see column c of Table 16) and the RMS σ of this velocity time history are calculated using the average transmission rate of each layer (j = i…n) (see paragraphs "0059" to "0 vik 075" of this specification) and the RMS of the reference point during an earthquake. v ik Regarding , ik , the RMS of the acceleration and velocity at the reference point during an earthquake can be rewritten in terms of the relationship with the expected value V of the maximum velocity and the expected value A of the maximum acceleration at the reference point during an earthquake using the peak factor.

[0143] [Table 16]

[0144] [Number]

[0145] [Number]

[0146] The RMS of the acceleration and velocity at the reference point during an earthquake is rewritten in terms of the relationship with the expected value V of the maximum velocity and the expected value A of the maximum acceleration at the reference point during an earthquake using the peak factor. The expected value V of the maximum velocity at the reference point during an earthquake maxk and the expected value A of the maximum acceleration maxk can be done.

[0147] [Number]

[0148] [Number]

[0149] <​​​ The calculated horizontal bearing capacity a (see column a in Table 17) is equal to the yield layer shear force (a (see column b in Table 17)). We calculate using the fact that it is equal to ). From equations 37 and 25,

[0150] [Table 17]

[0151]

number

[0152] Based on the above, the expected value of the hysteretic absorption energy of layer i due to a major earthquake, calculated from the k-direction component. W mik [Nm] can be calculated as follows:

[0153]

number

[0154] However, yield displacement e ikY This is expressed as the product of the yield deformation angle and the floor height. Also, the i-th layer k-th Regarding direction, R Yik : Yield deformation angle [dimensionless] H 0ik :Standard floor height [m] a (See Table 18): Inter-story displacement energy transfer coefficient with respect to reference point acceleration [dimensionless]

[0155] [Table 18]

[0156] Furthermore, regarding the k-direction component of the micro-motion time history of the upper surface of the area of ​​interest, T vik :Central period of the time history of micro-motion [sec] α vik : Bandwidth index of the time history of microtremor velocity [dimensionless] However, the bandwidth index is calculated by dividing the central frequency of its time history by the central frequency of its differential time history. The bandwidth index of the micro-motion velocity time history is the central frequency of the micro-motion velocity time history and the micro-motion acceleration. This is the ratio of the central frequencies in a time history.

[0157] Furthermore, regarding the parts supported by the layers, Σm: Mass [kg] B aik : Average acceleration transfer coefficient (see Equation 13) [dimensionless] B vik : Average velocity transfer coefficient (see Equation 14) [dimensionless]

[0158] Furthermore, regarding the k-direction component of the large earthquake motion at the reference point, the following parameters are related to the magnitude of the input. The properties are determined by the designer's judgment or by the standards set. s0: Duration of strong earthquake [sec] V maxk :Maximum speed [m / sec] A maxk :Maximum acceleration [m / sec 2 ] γ v : Peak factor of velocity time history [dimensionless] γ a : Peak factor of acceleration time history [dimensionless]

[0159] Furthermore, by dividing both sides of the above equation by Σm / 2, we obtain the hysteretic absorption energy per unit mass supported. The expected value of the velocity converted to V mik Obtain [m / sec]

[0160]

number

[0161] 7. Damage level (Seismic damping performance index, part 2) The degree of damage to a certain layer of a structure due to earthquake action is proportional to the hysteretic energy absorbed. Assuming that the ratio to the limit value is the degree of damage (I d ) can be used as a design indicator.

[0162]

number

[0163] Now, regarding the k-direction of the i-th layer: I dik :Damage degree [dimensionless] W mik Expected value of hysteretic absorption energy [Nm 2 / sec 2 ] W lik : Limit value of hysteretic absorption energy [Nm 2 / sec 2 ]

[0164] Limit value of hysteretic absorption energy W lik This refers to the restorative force of individual components or groups of components. Assuming it is a bilinear type as shown in Figure 8, we calculate by accumulating the respective limit values. It is possible.

[0165]

number

[0166] However, the limit value is twice the area of ​​the projection of line segment OYU onto the horizontal axis in Figure 8 for one iteration. Let this be the energy absorbed in return, and this n kj It is calculated assuming it is double. Here And with respect to the individual members j, or member groups j, in the k-direction of the i-th layer: n kj : Maximum number of repetitions [dimensionless] q kj :Strength [N] F jk :Toughness index [dimensionless] e Yj Yield displacement [m] RYik Yield deformation angle [rad] H 0ik :Floor height [m]

[0167] The expected value of the yield shear force (horizontal bearing capacity) in the k direction of the i-th layer is given in paragraph "008" of this specification. Since it is calculated from "1" to "0100", if you provide the toughness index of the layer and the limit cycle count, This allows us to calculate the limit of hysteretic absorption energy. Equation 47 groups the entire layer as one unit. Using formula 25,

[0168]

number

[0169] However, regarding the k-direction of the i-th layer N ik : Maximum number of repetitions [dimensionless] a (See column a in Table 17): Expected value of yield shear force (horizontal bearing capacity) [N] F uik :Toughness index [dimensionless] Σm: Mass of the supporting part [kg]

[0170] The damage level is calculated as the quotient of the expected value of the hysteretic absorption energy in Equation 44 and the limit value in Equation 48. Calculate it this way.

[0171]

number

[0172] Damage level I dik This refers to vibrations obtained from microtremor observations of the surrounding ground system in the direction of the i-th layer k. The average acceleration transfer coefficient B of the part that supports this characteristic aik , average velocity transmission rate T vik , and Interlayer displacement energy transfer coefficient a in the k-direction of the i-th layer relative to the acceleration at the reference point (see Table 20), velocity Central period T of time historyvik , and bandwidth index α vik This represents the characteristics of the input ground motion, indicating strong motion Duration s0, maximum speed V maxk and maximum acceleration A maxk and each peak factory γ v gamma a It is represented as follows. Furthermore, as a structural specification, the yield deformation angle R in the k-direction of the i-th layer is given. Yi k , and standard floor height H 0ik It uses the toughness index F, and its recovery performance is uik and limit repeated Number of times N ik It is represented as follows.

[0173] 8. Seismic Diagnosis Standards, Current Standards, and Seismic Motion Levels Reflecting Recent Earthquake Conditions Microtremor diagnosis (MTD2017) uses the observed microtremor time history to determine the vibration amplification characteristics of a structure. The energy transfer coefficient is quantified as a sample average. Furthermore, the vibration modes are visualized, and their inherent properties are identified. The period and bandwidth are measured. For seismic performance evaluation, the following are installed on the first floor, basement, etc. of the structure. Using the vibrations from a major earthquake at a reference point as input, the maximum elastic response is estimated from the energy transfer coefficient. The expected value of the structural seismic index is calculated. In addition, the average addition of the parts supported by the layer or section of interest is calculated. The degree of damage is calculated by estimating the hysteretic absorbed energy from the velocity and the predicted velocity. The setting of seismic motion levels is at the discretion of each designer, but the assumed levels of current standards, etc., are incorporated into micro-motion diagnosis. Converting and displaying the force values ​​is an effective method.

[0174] Table 19 shows the diagnostic criteria and the standard seismic motion levels that the current criteria are thought to assume. Expected values ​​of maximum acceleration, velocity, and displacement (Amax, Vmax, Dmax) and duration of strong ground motion The expected value (S0) is shown. Also, at the bottom, the seismic motion rate as seen from recent observed seismic motion is shown. Bell's case was shown as a reference. Regarding the diagnostic criteria, as mentioned above, by 1978 in Japan... This is an estimate based on observed seismic motion. Furthermore, regarding the current standards, the following applies to the establishment of those standards. The speaker's account and the notification spectrum (2015 edition of the Building Structure Technical Standards Publications, published by the National Official Gazette Sales Cooperative Association) This is estimated from the shape described in the technical standards commentary (pp. 488-490). Regarding recent observed seismic motion. This is estimated from strong motion observation records of the 2011 Tohoku earthquake and the 2016 Kumamoto earthquake. However, no statistical analysis or similar processes have been performed. Furthermore, the seismic motion levels in recent earthquake environments are an order of magnitude higher than the current standard level, and elasticity The current standard framework, which is based on maximum response, and the microtremor diagnostic framework use it as the input seismic motion. It's pointless. Seismic design for this level of earthquake motion must be done using a fundamentally different method than current laws. It is necessary.

[0175] [Table 19]

[0176] The role of microtremor diagnosis In rational seismic design, microtremor diagnosis plays the following roles.

[0177] (1) Post-completion inspection and additional countermeasures After the structure is completed, a microtremor diagnosis is performed to determine the vibration mode and vibration period (T c ), story shear force Distribution coefficient (A im ), response magnification (R amk , R vmk ), cumulative strength index a (see Table 20) , damage degree (I dm By measuring () and comparing it with the design calculations, the validity of the calculations and construction is confirmed. In addition, countermeasures will be added as needed. Note that each of the above indicators is calculated for the entire structure. In both cases, vertical array measurements installed in specific areas are used to understand the vibration characteristics of those areas.

[0178] [Table 20]

[0179] (2) Regular health checks and repairs Regular microtremor assessments will be conducted, and each of the indicators mentioned in the previous section will be measured. If deterioration of the structure is found, Repairs will be carried out. Furthermore, a microtremor diagnosis will be conducted again after the repairs to confirm their effectiveness.

[0180] (3) Diagnosis and seismic reinforcement of existing structures Microtremor assessments will be conducted on existing structures built under current or old seismic standards, and if necessary... Accordingly, countermeasures will be designed and constructed. In addition, measurements and diagnoses will be conducted before and after reinforcement to determine the effectiveness of the reinforcement. Confirm quantitatively.

[0181] (4) Analysis of the relationship between earthquake damage and the vibration characteristics of the ground and structures As an example, consider the case where a building that underwent microtremor diagnosis was damaged by an earthquake, and examine the relationship between the degree of damage and the diagnostic indicators. We will analyze the relationships and use the findings to revise future design methods, diagnostic methods, and standard values ​​for each indicator. [Examples]

[0182] 1) Target facilities and measurement methods Completed in 1972 (Showa 47), this building has one basement floor, four above-ground floors, and a total floor area of ​​838m². 2 (X direction 1 In a reinforced concrete hospital building (with a steel frame on the 4th floor, tentatively named Y Hospital) with 1 span (3 spans in the Y direction) Floors 12 to 4F are as shown in Figures 12 to 15, and this RC hospital building 11 In contrast, we will present the results of the microtremor diagnosis. A seismic diagnosis was conducted in April 2014. Although reinforcement plans were devised to achieve a value exceeding 0.6, construction could not be carried out while the hospital was operational. It was determined that it was possible to prevent collapse, and the SRF method (wrapping with polyester fiber belts) was used. The construction method involves "axial load-bearing reinforcement," which reinforces the main columns (see paragraph "0194" of this specification). It is being done.

[0183] Microtremor observations were performed using four microtremometers 21 in four different configurations as shown in Figures 12 to 15. In the first (measurement 1) and second (measurement 2) measurements, the A2 passage of each floor from the 1st floor to the 4th floor was... They are installed in a vertical array, one in each of the two locations and on the A4 paper. In Measurement 3, The points were installed at point A4 on the first floor and at points A2, A4, and B1 on the second floor. Measurement 4 was performed at point A on the first floor. They were installed at four different points and at points A2, A4, and B1 on the third floor.

[0184] The measurement process takes approximately two hours and involves sequentially setting up the instruments, taking continuous measurements for five minutes, and rearranging the instrument positions. Measurement and removal are being carried out using four types of instrument configurations. Before the reinforcement work was carried out, in August 2017... The hospital will be operating from 3 PM to 6 PM on the 8th. After the reinforcement, it will be on September 2, 2017. The work will take place from 2 PM to 4 PM on the 2nd. The construction period for the reinforcement work is from July 20th to September 3rd, 2017. Although the deadline is August 0th, as of August 8th, only preliminary preparations have been made and no construction has been carried out. As of September 22nd, the structural work was complete, with only a few finishing touches remaining.

[0185] Microtremor diagnosis involves analyzing the time history of the entire 5-minute recording observed at each point, in approximately 1-minute segments. Divide it into 5 to 7 parts that overlap with each other, and calculate each metric for each part. The mean and standard deviation were calculated for each measurement. The tables shown from Table 21 onwards show these mean values. The above measurements were taken before (before reinforcement) and after ( We went (after the reinforcements were made) to see the effect of the reinforcements.

[0186] The microtremometer observes the acceleration time history and uses a 10Hz high-cut filter and a 0.2Hz filter. After applying a low-cut filter (4th-order Butterworth), velocity and displacement are calculated using the linear acceleration method. This was obtained by numerical integration. Figures 16 to 22 show the floor plan and structural frame diagram of the target building. 'Expansion joints are installed along the street. Seismic assessment is for streets 1-4.' The process is divided into two parts: up to and beyond. The diagnostic results cited in this specification are 1 to 4'. This result covers the period up to that point.

[0187] 2) Performance indicators Table 21 shows the expected value of the cumulative intensity index shown in formula 32 (C T S D ) mik Before and after reinforcement The value C was obtained from the seismic diagnosis calculation. TU S D This is shown in comparison. Measurement 1 refers to the vertical A2 "Layer" and "Measurement 2" refer to a vertical array of A4 size. Table 22 shows the rate of change before and after reinforcement, and calculations. The values ​​are shown in comparison. Tables 23 and 24 show the augmented values ​​for the normalized input energy. Value W obtained from the microtremor diagnosis before and after. Komik The value W obtained by calculation Koik and changes before and after reinforcement The conversion rate and the calculation are shown in comparison. Tables 25 and 26 also show the expected value of the degree of damage (I d0m Values ​​before and after reinforcement and calculated value (I d ) and a comparison with the calculations before and after reinforcement are shown. Note that in Table 21 The values ​​in parentheses are those that take into account the second type of structural element. Also, the calculation of the degree of damage is based on the hysteresis absorption. The limit of energy is obtained from the strength and toughness of the member group, which were determined by seismic diagnosis calculations, using Equation 47. The calculations were performed, and the hysteretic absorption energy was calculated using a simplified formula (see paragraph "0199" of this specification). (See "). Furthermore, in the calculation of this example, the limiting acceleration used in calculating the hysteretic absorption energy is determined. In making this determination (see paragraph "0149" of this specification), the cumulative strength index is used instead of the lateral load-bearing capacity. The product of the indicator and the shape index (see formula 32) is used.

[0188] [Table 21]

[0189] [Table 22]

[0190] [Table 23]

[0191] [Table 24]

[0192] [Table 25]

[0193] [Table 26]

[0194] The reinforcement work involves installing highly ductile polyester fiber material (B) in the main columns of each floor from the 1st to the 3rd floor. This method (SRF method) ensures shear strength and axial load-bearing capacity by wrapping around a belt. The reinforcement design ensures that the verification ratio of all columns exceeds 1.0. The maximum value of the axial force test ratio is the collapse risk value (I f Design guidelines for reinforcement aimed at preventing collapse (referred to as "values") This is used as a guide. The two rightmost columns of Table 25 show I before and after reinforcement. fThe values ​​were listed. In the calculation, the axial load-bearing capacity of the column is Since this is the remaining axial load-bearing capacity under large deformation (F>3.0), it becomes zero before reinforcement for RC columns. Collapse risk level I f It is infinite.

[0195] Looking at the diagnostic calculations before and after reinforcement on the right side of Table 21, the reinforcement work has resulted in the following changes, except for the X direction on the first floor. Cumulative strength index C TU S D The value has decreased, which is due to the column-type wall or the column with a wing wall. This is because slits were cut and the columns were wrapped around them. However, C after reinforcement TU S D This is the diagnosis before reinforcement. The results of the cross-section were regrouped and compiled again, taking into account the increase or decrease in strength and toughness of the reinforced members. This is an approximate value. Note that the shape index S is determined by the cutting of the slit. D Changes have not been taken into consideration. The reduction in strength index due to reinforcement work is considered in this reinforcement design to be due to the fact that there is sufficient margin in strength in the Y direction. This is the result of aiming to prevent collapse by ensuring axial load-bearing capacity even if it means slightly reducing overall strength. Furthermore, as shown in Tables 25 and 26, reinforcement reduces damage level I d About 20-30% before reinforcement It decreased significantly to this extent, and after reinforcement, it is below the standard value of 1.0 in all floors and directions, and the reinforcement work This indicates that the damage was within acceptable limits.

[0196] The cumulative intensity index C calculated using diagnostic methods shown in Tables 21 and 22. TU S D This was obtained through microtremor diagnosis. The expected value of the cumulative intensity index (C T S D ) mik Let's compare the values ​​before reinforcement. Measurement 2 On the third floor, the microtremor diagnostic values ​​were about 40% lower, but the direction was almost the same as on the other floors. This can be seen. On the other hand, in Measurement 1, the first floor was almost the same, but the microtremor diagnosis results were different on the second and third floors. This is a significantly small value, representing only about 20% of the diagnostic calculation. This is because the measurement position is as follows: This is thought to reflect the surrounding structural features. As shown in the structural diagram in Figure 17, The X-direction of Measure 1 (2-way) is a frame with almost no walls. Also, there is an opening in the adjacent wall of 1-way. There are no walls in three of the large areas. On the other hand, the measurement 2 (four directions) X direction is almost entirely a wall frame. The same applies to the adjacent 4' frame. Measurement 1 (2-way, A-way) Y direction: There is no wall or The opening is large. On the other hand, in the Y direction of measurement 2 (4-way, A-way), there is an opening, but it is attached to a wall. This is also reflected in the shape indicators for seismic diagnosis. Specifically, the shape indicators shown on the right side of Table 21. S D The value is small, 0.63, on the 2nd and 3rd floors in the X direction. This is a result of the uneven distribution of walls in the X direction. Near the 2nd intersection, the inter-story displacement is large in both the X and Y directions.

[0197] Looking at the rate of change before and after reinforcement in Table 22, in measurement 1 (around 2), (C T S D ) mik but The improvement is almost uniform, around 20%. This is due to the column reinforcement using the SRF method shown in Figures 16 to 22. This results in 1 to 3 X-direction frames around the center of the column, and 2 Y-direction A-frames near the center. This can be attributed to the improved vibration characteristics and the resulting reduction in inter-story displacement relative to the design basis earthquake ground motion. On the other hand, in measurement 2, there was almost no change before and after reinforcement, (C T S D ) mik Decreasing However, looking at the absolute values ​​in Table 21, in Measurement 2, after reinforcement, both the X and Y directions were 1. The values ​​are consistent, with the second floor showing around 0.5-0.6 and the third floor around 0.2. Even in Measurement 1, Similarly, the ratio is consistent, with the first floor being around 0.6 and the second and third floors being around 0.2. The above applies to the SRF construction method. We believe that the reinforcement of the main pillars resulted in stable vibration characteristics.

[0198] Table 22 shows a comparison of the magnitudes of the values ​​obtained from diagnostic calculations and microtremor measurements, indicating that the eccentricity is small. On the first floor, both measurement 1 and 2 yielded almost the same values ​​as the calculations. This is due to the microtremor diagnostic method. and setting of the expected value of the maximum ground surface displacement of the seismic motion assumed by the seismic diagnosis (paragraph of this specification) This example demonstrates that the references "0113" to "0114" were valid. In the eccentric second and third floors, significantly different values ​​were measured between measurement 1 and measurement 2, and lead This example demonstrates that detailed structural characteristics can be understood through direct array observation.

[0199] Table 23 shows the normalized input energy W. K0ik and the permissible limit value W l0ik Looking at it, As shown on page 112 of the 2015 edition of the SRF Construction Method Design and Construction Guidelines and Commentary, published by the Institute for Quality Assurance of Construction. Normalized hysteresis absorption energy (hereinafter referred to as normalized input energy) W E The simplified formula The effect of seismic motion and structures on input energy is a uniform coefficient m. E = 5.0 Since this is assumed, the calculation assumes that the input energy does not change before and after reinforcement. In this specification, as shown in Equation 49, the strength of the structure, the response magnification, and the vibration bandwidth are reflected. The formula reflects the resonance, so it changes before and after reinforcement. However, in Table 23, green The W of Books E A i It is multiplied by and displayed as a value normalized only by the supporting mass.

[0200] As for the absolute value of the normalized input energy, it is the measurement 1 before reinforcement, which is greatly affected by eccentricity. In the X direction, the measured value is significantly larger, about 4 to 7 times larger than the calculated value, but otherwise it is almost the same. It can be said that this is the value. Therefore, this example is equivalent to the current standards shown in Table 19 for the microtremor diagnostic method. This suggests that the set values ​​for seismic motion levels are appropriate in terms of the degree of damage.

[0201] Tables 23 and 24 show the rate of change of the normalized input energy before and after reinforcement, and the eccentric Measurement 1, which has a significant impact, has uniformly decreased to about 60%. On the other hand, in Measurement 2, X There is a significant decrease on the 1st and 2nd floors in both directions, but an increase on the 3rd floor in both directions. The increase rate in the Y direction of 2 is large, approximately 7 times. These are directly related to the reinforcement shown in Table 22. Front and back strength (C T S D ) mik This reflects the changes in the standardized input. In calculating the limiting acceleration of energy, a cumulative intensity index is used, so this increase in intensity The result reflects the decrease. However, although the rate of increase in the Y direction is large, the absolute value itself is It is not significantly larger than the acceptable limit.

[0202] Let's look at the degree of damage shown in Tables 44 and 45. In the calculation, before reinforcement, in the X direction... Initially, the value exceeds the standard of 1.0, but after reinforcement, it falls below the standard in both the X and Y directions (damage becomes below the acceptable limit). )This is the result. According to the microtremor diagnosis, except for the X direction of measurement 1 which is affected by eccentricity, It is below the standard value. Measurement 2, 3rd floor Y direction, is 1.16, which is close to the standard value. You can think about it.

[0203] Based on the above, if this building were to experience a major earthquake as assumed by current standards, it would be affected by two nearby earthquakes. While vibrations in the X direction may cause damage exceeding the permissible limit, other parts will not be damaged. It is highly likely that this will remain within the acceptable limits. Note that this cannot be determined by microtremor diagnosis, see Table 4. Collapse risk value I shown in 4 f Since the value after reinforcement is below the standard value of 1.0, the current standard will be increased. It is believed that the building will avoid collapse even if subjected to seismic motion exceeding a certain width.

[0204] 3) Coefficient A representing the distribution of story shear force in the height direction i Table 27 shows the coefficient A representing the distribution of story shear force in the height direction. i Expected value of (A imk ) Reinforcement The values ​​before and after are used in equation 9 to obtain the absolute acceleration energy transfer coefficient a obtained by microtremor observation. (See Table 4) and the mass m of each layer of the structure j The result calculated from this is then applied to the current standard calculation formula (Formula 1). The values ​​obtained from (0) are shown in comparison, and Table 29 shows the rate of change before and after reinforcement, as well as the ratio of calculated to measured values. It is showing.

[0205] [Table 46]

[0206] [Table 47]

[0207] [Table 48]

[0208] Let's look at the measured values ​​before and after reinforcement. In Measurement 1, the maximum value was It has only changed by about 2%. In measurement 2, it increased by 10% to 20% on the 3rd floor, but 2 The change is less than 5% on each floor. Looking at the ratio of calculation to actual measurement, on the second floor, the measurement points and the presence or absence of reinforcement differ. Regardless, they are almost identical. On the other hand, on the 3rd floor, before reinforcement, both measurements 1 and 2 were more accurate than the calculations. The measurement was about 10% smaller, and after reinforcement, in measurement 2, the actual measurement and calculation matched, or in the Y direction, 1 It has grown by about 0%.

[0209] Looking at the absolute values ​​of each of the above figures, the measured values ​​and the calculations are in almost agreement. This is because the story shear force A measurement method using microtremor measurements of coefficients representing the distribution in the height direction indicates the maximum for low-rise buildings under current standards. This indicates that a uniform seismic intensity distribution, which is thought to be the response layer shear force distribution, has been measured. Furthermore, the changes before and after the reinforcement of the third floor, and the comparison with the calculations, show that the strength of the third floor was particularly increased by the reinforcement work. The effect of modifying the large structure by cutting slits to bring it closer to the second floor or below is evident. It is thought that this is the case.

[0210] For measurement 2, the 3rd floor Y direction is measured as A i (A imk ) is considerably larger than calculated This means that by cutting a slit, the structure becomes such that the vibration of this part is amplified. This indicates that the measured values ​​of the intensity index shown in Table 21 (C T S D ) mik of The normalized input energy W decreased (0.60 → 0.20) as shown in Table 23. K0ik Increase ( 5.4→37.9), and damage level I shown in Table 25 d0ik Increase (0.80 → 1.16) This is evident in the following: However, after cutting the slits, the columns were wrapped using the SRF method. According to the same table, the risk of collapse is below 1.0 on each floor. Also, according to the same table, based on microtremor observations Regarding the area around measurement 2, it was confirmed that the degree of damage on each floor was almost below the standard value (1.0). Yes, it is possible. Also, near measurement 1, the value in the Y direction is below 1.0. X in measurement 1 Regarding the fact that damage in a certain direction is somewhat predictable, we will apply seismic-resistant coating to one wall using the SRF method. It is effective to absorb vibrational energy by doing so. This reinforcement was carried out for the purpose of preventing collapse. Therefore, from the perspective of damage control, we would like to implement the above measures in future construction work.

[0211] 4) Average acceleration, average velocity transmission coefficient B aik B vik From the microtremor observation results, the average acceleration and average velocity transfer coefficient are calculated using equations 13 and 14. The values ​​before and after reinforcement are compared and shown in Tables 30 and 31. These are the i-th layer of the structure. The spatially average acceleration, or velocity, of the part supported by it, and the ratio of that to the acceleration, or velocity, of the reference point. Therefore, the first-order value is the average response ratio of the entire structure. Also, A i is average acceleration Energy transfer coefficient B aik These are values ​​where the values ​​of each floor are normalized by the values ​​of the first floor (see formula 17). ).

[0212] [Table 30]

[0213] [Table 31]

[0214] This building is located on Type 2 ground, and the natural period of the ground is T c = 0.6 sec, building height h=14.3m, of which the steel frame portion is 2.95m, the height of the floors (excluding the basement) that are steel framed. The ratio λ to h[m] is 0.206, therefore, according to the current standard formula (see formula 12), The building's natural period is calculated as T=h(0.02+0.01λ)=0.32 sec. Therefore, T <T c Therefore, the vibration characteristic coefficient R t = 1.0 is calculated, and the acceleration response magnification is, under current standards It is concluded that the standard value at the time of enactment is 2.5 to 3.0.

[0215] Based on the above, let's look at the measured response magnification, which is the first-order value. Both acceleration and velocity are approximately the same. These are the values, and in Measurement 1, before reinforcement it was 2.5~4.0, and after reinforcement it was 2.0~3.7. In Measurement 2, the values ​​were 2.0-2.4 before reinforcement and 1.6-2.2 after reinforcement. (Absolute value) This is roughly equal to the current standard assumption of 2.5 to 3.0. This confirms the validity of the microtremor diagnostic method. It is showing.

[0216] Next, let's look at the rate of change before and after reinforcement. As shown in Table 31, each floor supports Regarding the partial acceleration response magnification, only the Y-direction of measurement 2 after reinforcement showed a slight increase (7%). Although it is present, at other measurement points, it has decreased to about 70% to 90% in all directions. Also, depending on the speed Regarding the answer magnification, there is a slight increase in the Y direction of measurement 2, but a decrease in other directions. The numerical values ​​quantitatively demonstrate that the structural system has changed to be less susceptible to earthquake damage due to the reinforcement work. These values ​​are used to calculate the degree of damage, and each of the fingers mentioned in the previous section is represented accordingly. The above characteristics are reflected in the standard values.

[0217] 5) Micro-vibration characteristics Table 32 shows the RMS of microtremor acceleration before and after reinforcement, and the change in energy transfer coefficient before and after reinforcement. The rate is shown. Table 52 shows the central period and bandwidth index of the micro-acceleration before and after reinforcement. Tables 34 to 37 show the characteristics regarding micro-motion velocity and displacement. Dynamic acceleration is measured, and velocity and displacement are processed using a 10Hz high-cut filter and a 0.2Hz low-cut filter. The result is obtained by filtering and then integrating using the linear acceleration method. In each table, "floor" refers to the floor of that floor. It is the floor.

[0218] [Table 32]

[0219] [Table 33]

[0220] [Table 34]

[0221] [Table 35]

[0222] [Table 36]

[0223] [Table 37]

[0224] The energy transfer rate is calculated using the RMS of the reference point as defined in paragraph "0067" of this specification and the energy transfer rate for each floor. The RMS ratio, that is, the amplification factor of the vibration, is the element used to calculate each of the diagnostic indicators shown in the previous section. It is.

[0225] The central period is given by Equation 1, and the bandwidth index is given by the method described in paragraph "0156" of this specification. This is calculated as follows. The central period is the expected value of the zero-crossing period for a steady-state Gaussian process. Yes, the bandwidth index is 1.0 for a sine wave and 0 for white noise. It approaches zero. Looking at the changes before and after reinforcement, the acceleration is almost the same before and after, or slightly different. It is getting bigger. Also, regarding the speed, the central period is slightly larger in measurement 1, Measurement 2 shows a slight decrease. The bandwidth index is increasing at both observation points. That is, The width has narrowed. Looking at the micro-motion displacement, the central period has clearly decreased after reinforcement. The bandwidth is increasing. This is because the vibration is approaching a sine wave due to reinforcement, and the structure This indicates that the system's rigidity has improved.

[0226] Tables 38 to 40 show the central period measurements for microkinetic acceleration, velocity, and displacement, as well as the current standard for primary fixed period. The calculated values ​​for periodic vibrations are shown for comparison. Structures subjected to microtremors or seismic motion will experience irregular vibrations. As it moves, the central period of displacement, velocity, and acceleration increases with bandwidth (as specified herein). (See paragraph "0156"). In this example, around the value of the first natural period calculated using the current standard formula. There are central periods for acceleration, velocity, and displacement. Therefore, since almost the same central period value is obtained for each point, each floor, and each direction, the entire building It is thought that the body is vibrating in its own unique mode.

[0227] [Table 38]

[0228] [Table 39]

[0229] [Table 40] [Examples]

[0230] 1) Target facilities and measurement methods The measurement target is an 11-story reinforced concrete building completed in 1994 (2 spans in the X direction, 1 span in the Y direction). The first floor is a piloti-style apartment building with a parking garage (see Figure 24). However, in the X direction There is a stairwell, etc. Between the end of August and September 2017, two independent columns on the first floor (A2, A3) It was wrapped using the SRF method (see lines 1 to 3 of paragraph "0194" in this specification). 2 Floors 1 through 11 are residential units, while the two main walls from floors 2 through 10 are earthquake-resistant walls. The measurement was performed by installing instruments near the B2 and B3 columns on each floor, forming two vertical arrays, and Three instruments are placed on each floor near B1, A2 (see Figure 25), and B3 on the rooftop. This is a three-point plane observation. Before reinforcement, on August 25, 2017, four instruments were used, and after reinforcement, the same year... The test was conducted on December 19th with 12 units. Note that access to the second floor was restricted near B2. (Figure 26) The first-floor plan shows the locations of the reinforced columns and the placement of the instruments.

[0231] 2) Measurement results Figure 27 shows the horizontal trajectories of the micro-motion displacement of the reinforced B3 vertical array over a 6-minute period for each floor. The measurement is displayed in three parts, each lasting two minutes. The amplification progresses from the first floor to the upper floors. From this, it can be seen that each point is undergoing approximately circular motion.

[0232] Table 41 shows the energy transfer coefficients for the B2 vertical array and the rooftop surface, and Table 42 shows the energy transfer coefficients for the B3 vertical array. (The ratio of the micro-displacement RMS of the first floor and the floor below) and the rate of change before and after reinforcement are shown. Note that Table 41 shows the surface and The column indicated represents the energy transfer coefficient related to rotation around the coordinate axes of the rooftop surface. After reinforcement, The reduction around the X-axis is approximately 1 / 10, and the reduction around the Y-axis is approximately 1 / 30. (Tables 41 and 4) The columns below RF in section 2 show the energy transfer coefficient of translational motion and the ratio before and after reinforcement, but B2, B3 In both cases, the decrease is greater on the upper floors. These are the SRF construction method, and the ground floor piloti area By wrapping around two independent columns (A2, A3), especially column A2 which penetrates the lower floor wall, the vibration mode was reduced. It shows a consistent effect.

[0233] Furthermore, Figure 27 shows the roof surface before reinforcement, and Figure 28 shows the roof surface after reinforcement, with the movement of the roof surface measured at three locations on the roof surface. Displacement data (XYZ 3 components) from a micromotor sensor is entered into the structural analysis result visualization software AVS. This is a depiction of a single moment that has been visualized (animated). Observing the results, before reinforcement, the roof surface vibrates significantly up, down, left, and right, but after reinforcement, it is almost horizontal. It can be seen that it is vibrating in a circular motion within the plane. This is represented as a plane in Table 1.3.9.1. The energy transfer coefficients around the X and Y axes decreased to 11% and 3%, respectively, before and after reinforcement. This clearly demonstrates that...

[0234] [Table 41]

[0235] [Table 42]

[0236] Tables 43 and 44 show the reinforced story shear force distribution coefficient (Ai) and the central period of micro-motion displacement. (Tc) measured value and primary natural period (T) calculated value according to seismic standards (paragraph "003" of this specification) (Contents described in "8" to "0058"). The measured values ​​for A1 are almost identical up to around the 5th floor. However, in the upper floors, the magnitude is clearly smaller than the calculated value, and the amplification of seismic motion is less, that is, piloti This indicates that it is a vibration mode specific to the structure. The central period differs slightly between the lower floors and the rooftop. Although it is attached, the temperatures on both B2 and B3 on the upper floors are almost constant and close to the calculated values.

[0237] [Table 43]

[0238] [Table 44]

[0239] Table 45 shows the story shear force coefficient of the first story when the horizontal load-bearing capacity is reached near B3 (C ui 1km ) is the measured value (Equation 27). For floors 2 to 10, the Y direction is compared to the X direction. The high values ​​reflect that the partition walls between the 2nd and 10th floors of the apartments are earthquake-resistant walls in two different configurations. Also, the 4th and 5th floors are lower than the other floors. This building is undergoing concrete pouring work on the 4th and 5th floors. During the work, heavy rains occurred, interrupting construction. The workers withdrew and resumed work about a week later. It is said that the quality of the concrete deteriorated due to the heavy rain and the interruption, reducing its horizontal load-bearing capacity. This is thought to have led to a decrease in (strength).

[0240] [Table 45]

[0241] Tables 46 and 47 contain the contents described in paragraphs "0119" to "0172" of this specification, and the The velocity-converted value of the expected value of the hysteresis absorption energy derived from the content (Vmik ) and degree of damage (I dik ) is shown. Note that the nature of the input ground motion is based on the assumed values ​​of the current seismic standards, and the duration of strong ground motion is shown. s0=7sec, maximum speed V max =0.8m / sect, maximum acceleration V max =4.0 m / sec 2 Furthermore, considering that it is a building that complies with the new seismic standards, each floor and each direction is Toughness index F uik The value is set to =3.0. Note that the limit of iterations is 2nd order or higher. Considering that it is a steel-reinforced concrete column, N ik =15 The first floor is SRF construction From experiments that confirmed the effectiveness of reinforcement by the method, N ik I set it to =45.

[0242] Tables 46 and 47 show the input ground motion as a value representative of recent seismic conditions, specifically strong motion continuum. Duration s0 = sec, maximum speed V max =1.2m / sec, maximum acceleration A max =10 m / sec 2 (See Table 19). The toughness index and limit cycle count are as described above. That was correct.

[0243] Table 46 shows the calculation results for hysteretic absorption energy, which is for the seismic motion assumed by the current standards. The result was that there was almost no absorption in the Y direction (the yield displacement was not reached). Regarding the X direction, the 4th and 5th floors and the top floor, where concrete construction defects are suspected, have yielded. The result is as follows. Furthermore, for the seismic motions that represent the recent seismic environment shown in Table 48, B3 attached. The results indicate that a large amount of absorbed energy is generated except for the intermediate floor in the nearby Y direction.

[0244] The damage levels in Tables 47 and 49 indicate whether the energy absorbed by each layer falls within the damage limit. However, for the seismic motion assumed by the current standards, both B2 and B3 areas are affected in both the X and Y directions. The result is that it falls below the limit value (1.0). In this sense, the current standard (new seismic standards) It can be said to be compliant. However, there are suspected concrete construction defects on the 4th, 5th, and top floors. The result indicates that it is almost at its limit. On the other hand, Table 49 shows the seismic motions that represent the recent seismic environment. Therefore, in the Y direction near B3, it stays within the limits except for the 4th and 5th floors, but in the X direction it is large This results in damage. Furthermore, this building has a piloti structure, and as shown in Table 48, large on the first floor Although calculations show that hysteretic ball energy is generated, even so, wrapping the columns with the SRF method... The reinforced first floor and the second floor directly above it both fell within the limit limits. Regarding the floors, measures such as re-covering should be taken to reduce damage. It is the result.

[0245] In the example above, the limits of the number of cycles and the toughness index for each component are hypothetical, but for similar components, This can be determined by observing the load displacement history and the degree of damage obtained from repeated loading experiments. It is possible. Also, the maximum acceleration, velocity, displacement, and duration of strong ground motion are calculated by combining the seismic motion observation results. We can decide together.

[0246] [Table 46]

[0247] [Table 47]

[0248] [Table 48]

[0249] [Table 49]

[0250] As described above, the degree of damage in the present invention is the degree of damage to the structure according to the level of seismic motion. The effectiveness of countermeasures against this was measured by various transmission rates and limit loads obtained through micro-tremor observation of the structure. This can be quantitatively demonstrated using the number of returns and ductility index. It contributes to the rationalization of seismic design. That is the case.

[0251] The following describes an example of applying the method of the present invention to a concrete block wall.

[0252] 1. Installation Figure 29 is a schematic diagram showing the arrangement of the block wall, foundation, ground and microtremor meter. The motion sensor 1 is placed on the top 17 of the block wall 16, the foundation 18, or the ground surface 20 near the foundation 18. Install it on a flat surface. When installing the micro-vibration sensor 1 on the top 17 of the block wall 16, the legs 1 of the micro-vibration sensor 1 Position a so that it lies on the center line of the top 17 of the block wall 16. Top 17 and surrounding ground 2 When installing on 1, and when the frig on the foundation 18 is large, a steel plate shall be used.

[0253] 2. Measurement Simultaneous measurements will be taken for approximately 6 minutes on the top 17 and the foundation 18. The data will be collected in the same way as for the building diagnosis. Then, the analysis is performed using free kicks and an Excel spreadsheet for microtremor diagnosis. At this time, the floor height is the block. Height of wall 16 (z coordinate of microtremor 1 at the top 17 and microtremor 1 at the foundation 18 or surrounding ground 21) Let H be the difference between the two values, and assume that the weight supported by the layer is zero. The calculation involves calculating the velocity, displacement, RMS, central period, and transmission coefficient for each time history. The inter-story displacement or the absolute displacement at the top is taken as the time history d(t) of interest, and the foundation 17 or surrounding The measurement point of the edge ground 21 (see No. 1 in Figure 29) is used as the reference point, and the transmission coefficient (h) is calculated relative to it. dk Calculate ).

[0254] 3. Diagnosis Reference point displacement x for a major earthquake assumed by the diagnostic criteria Gkmax When set to 2.5 cm The relative or absolute displacement of the top 23 is predicted using the following formula (yellow book, formula 1.4.8).

[0255]

number

[0256] However, in the above equation, d(t) = y2(t) - y1(t), h dk =RMS[d(t)] / If we use RMS[y1(t)], the relative displacement can be predicted.

[0257] Also, d(t)=y2(t), h dk =RMS[d(t)] / RMS[y1(t)] and Then, the absolute displacement can be predicted.

[0258] Here, d(t), y2(t), and y1(t) are the relative changes between the vertex 23 and the reference point, respectively. The absolute displacement of the top 23 and the y-direction component (orthogonal to the block wall 22) of the absolute displacement of the reference point are as follows: be.

[0259] The relative displacement between the top 16 and the foundation 17 during an earthquake, calculated using formula 50, or the absolute displacement of the top 16 Based on the expected value relative to displacement, the risk of block wall 15 toppling over (I tbw Calculate ).

[0260] If D / H is the average value of the tipping limit slope, then the following equation holds.

[0261]

number

[0262] However, D[cm] is the width of the block wall 15 (see Figure 29), E[d Gkmax ]teeth, The absolute displacement of the top 16 of the block wall 15 in the event of a major earthquake as assumed by the seismic diagnosis standards is the expected value of relative displacement, and a (see Table 50) is the tipping limit when the tipping limit slope is D / H. This is a top displacement.

[0263] [Table 50] [Examples]

[0264] Next, a specific example of microtremor measurement using the present invention method applied to a concrete block wall will be described below.

[0265] The specifications are as follows: Location: Block wall of a certain apartment building in Hirakata City, Osaka Prefecture Structure: CB construction Thickness: 150 [mm] Extension: ~15000[mm] Height: 1870 [mm] (The height from the reference measuring device to the top is 1790 [ mm] Block size: (thickness x length x height) 150 [mm] x 390 [mm] x 200 [mm] Retaining wall: None Four micro-motion measuring devices were used.

[0266] Figures 30(a) to (c) show the actual measurement conditions at each measurement point, and among them (a) shows the situation at measurement point 1, (b) shows the situation at measurement point 2, and (c) shows the situation at measurement point 3. These are shown respectively. Also, Figure 31 shows the block wall viewed from above, corresponding to Figure 30. This is a schematic diagram illustrating the arrangement of the measuring device (micro-motion meter).

[0267] The risk of the block wall collapsing was calculated using formula 51. This is shown in Table 51.

[0268] [Table 51]

[0269] According to Table 51, the risk of tipping over is below 1.0 in all cases, and the ground conditions assumed by the seismic diagnosis standards are not met. The vibration (maximum displacement of 2.5 cm) was determined to not pose a significant risk of tipping over. However, There is a risk of tipping over in earthquakes with ground motion exceeding this level (for example, recent earthquakes).

[0270] About the role of microtremor diagnosis The method that assumes the action of an earthquake is an inertial force proportional to ground acceleration (inertial force approximation) is used in both new and old stagnation Regardless of the seismic standards used or whether dynamic or static calculations are performed, this forms the basic principle of current seismic design. Combined with numerical computation methods such as the finite element method and the development of digital computers, 196 From the latter half of the 2000s to the present, structures of a scale, shape, and materials never before seen on Earth. This became the driving force behind the construction of these facilities in earthquake-prone regions around the world, including in our country. The new seismic standards stipulate that the collapse process of structures must be tracked numerically, requiring specialized software. Seismic calculations have become so complex that structural design is impossible without them. Even experts struggle with structural seismic indices and It is physically impossible to fully understand the lateral load-bearing capacity or the detailed calculation process of dynamic analysis. Currently, we have no choice but to trust the numbers that computers produce. On the other hand, from the end of the 20th century to this century During that period, seismic activity intensified, and both the magnitude and duration of observed ground motion increased to 197 The current standards, which are based on earthquake observations up to the 2000s, are several times to an order of magnitude higher than the assumptions made. .

[0271] At recent seismic ground motion levels where ground acceleration exceeds 1G, the inertial force approximation does not hold true. The incompatibility of designing structures and ground systems that intend to undergo three-dimensional motion by separating them into x-direction and y-direction. Reason also becomes more prominent. Fundamentally, the spatiotemporal scale of a major earthquake is different from the scale of individual structures. It's not comparable. If you try to capture the seismic motion of a major earthquake on a structural scale, it's extremely difficult to do so. It becomes a disaster. The phenomena caused by a major earthquake can result in discontinuous large changes in conditions. It changes rapidly. This is called a statistical phenomenon. Based on calculations using the current standard method, Constructing structures of a scale and form that have never existed before is also challenging in terms of input seismic motion. The assumptions and models used in the calculations are not necessarily rational.

[0272] The study of modern earthquake-resistant structures, which began in Japan following the 1891 Nobi earthquake, focused on reinforced concrete. Combined with the development and improvement of design and construction techniques for cleat materials, it withstood the Great Kanto Earthquake of 1923. By the 1960s, major cities such as Tokyo had built heavy buildings based on low-to-medium-rise reinforced concrete structures. It created a magnificent landscape. However, with the lifting of height restrictions in 1963 and the 1964 Tokyo Olympics... In addition, the high economic growth policies and the rapid spread of concrete pumping methods helped, Buildings are being demolished, and overcrowding and the construction of high-rise buildings are progressing rapidly.

[0273] In the area affected by the magnitude 7 earthquake during the 1995 Great Hanshin-Awaji Earthquake, the current standards are more than three times higher than anticipated. Even when subjected to earthquakes, approximately half of low- and mid-rise reinforced concrete buildings remained undamaged, excluding pilotis, even under the old standards. Yes, but only a few percent have collapsed. These include civil engineering structures such as Shinkansen elevated bridges and expressways. Roads and other structures collapsed, but the earthquake was several times stronger than anticipated in the design, and the ground, including the old riverbed, was also affected. The damage was concentrated in the areas most affected, and it is said that collapse was inevitable. The same was true during the 2011 Great East Japan Earthquake. Even under the old standards, buildings would not have collapsed due to seismic activity. Only a few have experienced earthquakes of magnitude 5 or higher. Of the 98 buildings, none collapsed, and 97 were almost undamaged and continued to be used. School buildings, apartments, etc. that had undergone seismic reinforcement became unusable and were demolished or left unfinished after major repairs. It was deemed necessary. Furthermore, the Tohoku Shinkansen had already undergone seismic reinforcement using steel plates on its bridge piers. After the earthquake, the line became inoperable due to the destruction of beams and damage to the overhead structures such as overhead lines, and it took more than 50 days to restore service. It is.

[0274] The need for a fundamental revision of the current seismic standards is stated in the aforementioned diagnostic criteria. This section discusses the characteristics of microtremor diagnosis and how it can be used in rational seismic design, supervision, and reinforcement work. Describe the role you will play.

[0275] (1) Response calculation During an earthquake, the most important performance requirements for structures are minimizing damage and allowing them to continue to be used. In recent earthquakes with ground acceleration exceeding 1G, indicators such as the lateral bearing capacity are used. Using this method, tracking the structure after it has become nonlinear is not only physically difficult, but also From the perspective of ensuring continuity of use, structures that do not cause nonlinearity itself, i.e., diagnostic criteria As stated, buildings with high structural strength (and therefore higher hurdles for nonlinearization) are desirable. What can be understood from response calculations is that, in response to a specific seismic motion, or a general seismic motion, the structure Vibration modes, maximum acceleration, velocity, displacement, and hysteretic absorbed energy when the constructed ground system responds linearly. This includes energy, etc. Microtremor diagnosis allows us to directly obtain the information necessary for calculations within the elastic range. Furthermore, it is easy to compare calculations with actual measurements.

[0276] (2) Earthquake motion assumptions The action of an earthquake is a proximity action. From the epicenter to the surrounding ground, and from the surrounding ground to the foundation, soil Based on the actual phenomenon of energy being transmitted from the platform to the columns on the first floor, from bottom to top, the assumed seismic motion (calculation) It is reasonable to determine the seismic motion to be used. As the current building standards do, The method of predetermining the response acceleration or response spectrum of a fabricated object is not only illogical, but also... Furthermore, excessive seismic forces can be generated in structures, posing a risk of collapse or significant damage. Then, the seismic motion is numerically synthesized to match the response spectrum, and time history response analysis is performed. That would be putting the cart before the horse.

[0277] One method for defining the assumed seismic motion is to use the engineering bedrock surface, and in limit state design calculations, etc. It is used. However, the seismic motion that a structure actually experiences is the seismic motion of the engineering bedrock directly beneath it. Furthermore, it is affected by a wide range of substrate surfaces that extend in three dimensions. Calculation, that is, three-dimensional ground vibration analysis calculation, is almost impossible. Instead, first-order When calculating the original overlapping reflections, the difference between the seismic motion actually input to the structure and the calculated seismic motion is used. The differences are bound to become extremely large.

[0278] In microtremor diagnosis, input vibrations are applied to the foundation of the structure. Furthermore, the properties of the assumed earthquake motion are considered. In this case, maximum acceleration, maximum velocity, maximum displacement, and duration of strong earthquake are used. However, the assumptions are made. Even if specific numerical values ​​are set regarding the magnitude of seismic motion, etc., these are merely expected values ​​(average values). ) This is the result. Actual seismic motion will be this value plus or minus a large amount of variation.

[0279] (3) Performance evaluation In recent earthquakes where ground acceleration exceeds 1G and the duration is several minutes or more, wooden structures are vulnerable. Up to super high-rise buildings, visible displacement is unavoidable, and numerous repeated displacements occur. Evaluation indicators that clearly incorporate what happens are needed. Furthermore, indicators should be applied to each layer of the structure. Instead of aggregating the data, performance evaluation must be performed using a collection of indicators related to individual components and parts. There is a need. In microtremor diagnosis, the degree of damage is defined and used as an indicator to directly evaluate the continued usability of the equipment. This is called the seismic damping performance index.

[0280] (4) Rational earthquake-resistant structure With recent seismic ground motion levels, structures that exhibit the type of total collapse assumed by current standards are not being constructed. Therefore, calculations show that collapse is unavoidable, and continued use is not feasible. The structure is pre-planned to include parts that move and absorb seismic energy, and parts that keep deformation within the damage limit. This structure is rational. In a well-formed reinforced concrete (RC) structure, the top and base of each column act as bending hinges, causing overall deformation. This creates movement. In eccentric structures, such as pilotis, the capitals and bases of the columns move in the areas with fewer walls. In the piloti stage, the eccentrically swaying part vibrates greatly and absorbs energy, thus other The deformation of the floors and parts can be kept to a minimum. In reinforced concrete (RC) structures, unless the site is in bedrock, the rigidity of the structural frame is sufficiently greater than that of the surrounding ground. Therefore, in addition to the vibration of the structure as described above, there is also energy from the boundary (foundation) between the surrounding ground and the structure. —We want to plan for absorption systematically. We want to incorporate the relative movement of the foundation and the surrounding ground into the design. This is effective. In wooden structures, the deformation and energy absorption capacity of individual joints and nailing points is large. Therefore, the joints and nailing points should have three-dimensional mobility and resilience. Also, the soil from the foundation We want to specifically incorporate the reduction of seismic effects caused by the platform's elevation into the design. Microtremor diagnosis determines the cumulative strength index and degree of damage of each part of the structure in relation to the assumed seismic motion under current standards. By calculating and visualizing the natural vibration modes, the antinodes and nodes of the vibration are extracted, and key members and connections are identified. By reinforcing the joints to provide energy absorption capabilities, the structure can withstand major earthquakes. This allows for a structure with energy absorption capabilities. The SRF method can be used for the above reinforcement. It is effective.

[0281] (5) Inspection of new construction and inspection of structural renovation work After the structure is completed, or after renovation work is finished, a microtremor diagnosis is performed to determine the vibration motor. , vibration period (T m ), story shear force distribution coefficient (A im ), response magnification (R amk , R vmk ), cumulative strength index (C T S D ) m , damage degree (I dm ) is measured and compared with the design calculations, This will confirm the validity of the calculations and construction work, and provide information to determine whether additional countermeasures are necessary. This can be done. Furthermore, each of the above indicators is calculated for the entire structure, as well as for indicators installed in parts. Vertical array measurements are used to understand the vibration characteristics of that section. Currently, intermediate and final inspections of new constructions involve inspectors visually checking for consistency with the drawings. It remains at that stage. The same applies to seismic retrofitting. Based on microtremor diagnosis, the inspector's judgment... Objective numerical values ​​can be added to the indicators.

[0282] (6) Regular health checkups Regular microtremor assessments will be conducted, and each of the indicators mentioned in the previous section will be measured. If deterioration of the structure is found, This will be used as a basis for deciding whether to carry out repairs. Furthermore, a micro-vibration diagnosis will be conducted again after the repairs to confirm their effectiveness. This can be used as reference material.

[0283] (7) Seismic diagnosis and seismic retrofitting design of existing structures Microtremor assessments will be conducted on existing structures built under current or old seismic standards to determine seismic resistance. This document will be used to evaluate performance and, if necessary, to design and construct countermeasures. It will also include data before and after reinforcement. Measurement and diagnosis can be performed to obtain data for quantitatively confirming the reinforcement effect. Currently, seismic assessments are conducted over a period of several months and at a cost of several million yen or even more than ten million yen. This is because the calculations are complex and require a high level of expertise. If we simplify the process and make a judgment based on the indicators obtained from microtremor diagnosis, then the cost and time... It can be significantly reduced.

[0284] (8) Analysis of cases with and without damage In the future, as a large number of actual measurement examples are accumulated, correlation analyses will be conducted between actual damage and no damage in actual earthquakes. Therefore, the ratio of calculations to the diagnostician's judgment is minimized, and seismic diagnosis and repair locations are primarily based on microtremor diagnosis results. It is expected that this will enable renovation designs such as extraction of certain elements. Furthermore, it will enable the design of renovations during new construction, after renovation, and during periodic inspections. This will increase the role of microtremor diagnosis and make it possible to narrow down calculations and judgments to the necessary range. .

[0285] Regarding the challenges of seismic standards and solutions using the SRF method (bandage reinforcement), April 2017 He has published a paper titled "Revolution in Earthquake Resistance." Along with microtremor diagnosis, he has rationalized earthquake-resistant design and the ground We hope this will help reduce the economic burden and risks associated with earthquakes.

[0286] As is clear from the detailed explanation above, according to the present invention, the diagnosis of existing structures • Expected values ​​of cumulative strength index and structural seismic index used in seismic retrofitting design, and current new construction design The expected value of the distribution coefficient of story shear force in the height direction used, and the ability to directly evaluate the continued usability of the structure. By defining the degree of damage to be evaluated and directly obtaining its expected value from the micro-tremor measurements, Therefore, by observing vertical arrays installed in each part of the structure, the parts (zones) of each floor are The results, which allow for the measurement of vibration characteristics, intensity, and degree of damage, are relevant to the soundness and safety of structures. This method offers far more detailed seismic design and reinforcement than conventional methods that directly apply external forces to objects, Seismic evaluation tailored to individual vibration characteristics, seismic design, and the continued use of structures (implementation of seismic reinforcement work) This allows for direct, inexpensive, and rapid evaluation of the most important target performance.

[0287] In other words, according to the present invention, by using the above indicators, it is possible to determine the value after new construction, after renovation work, and fixed During periodic assessments, seismic assessments can be performed at a much lower cost and more quickly than current seismic assessments. Therefore, it becomes possible to carry out rational seismic reinforcement design and seismic design for newly constructed structures. [Explanation of symbols]

[0288] 1 Microtremometer 1a Foot 2 Analyzer 10 Structures 10a,10b,10c layer boundary surface 11. Reinforced concrete hospital building 12 1st floor 13 2nd floor 14 3rd floor 15 4th floor 16 Block wall 17 Top 18 Basics 20 Ground surface 21. Surrounding ground

Claims

1. In a method for evaluating the performance of a structure through continuous microtremor observation, The seismic performance of the structure is evaluated based on the observations, using the root mean square (RMS) of these time histories to calculate an estimated value A of an index used in the seismic design of the structure, and using the ratio of this value A to the value B of the index used at the design stage, The aforementioned index is the acceleration response magnification R specified in the current standards. ａｍｋ And, The estimated value A of the index used in the seismic design of the aforementioned structure is the acceleration response magnification R when reduced to a single-degree-of-freedom system. ａｍｋ This is the expected value, Acceleration response magnification R when reduced to a single-degree-of-freedom system ａｍｋ The expected value is In formula 13, [Number 13] And, Average acceleration transmission coefficient B with j = 1 ａｉｋ However, the ratio of the mean absolute acceleration of the structure, a (see column a in Table 7), to the absolute acceleration of the reference point, b (see column b in Table 7) (however, [Table 7] Here, mj is the mass of the j-th layer, a (see column a in Table 5) and b (see column b in Table 5) are the energy transfer coefficients of acceleration and velocity in the k-direction of the j-th layer, respectively, and B ａｉｋ B is the average acceleration energy transfer coefficient. ｖｉｋ This is called the average velocity energy transfer coefficient. However, the energy transfer coefficient is the ratio of the RMS of the microtremor time history of interest to the microtremor time history of the reference point. In microtremor diagnosis, it is assumed that this is preserved at the time of the maximum elastic response due to seismic motion input, and assuming an appropriate peak factor, the maximum response of the time history of interest is calculated by multiplying the maximum input value of the reference point by the energy transfer coefficient. [Table 5] ） That is, A diagnostic and evaluation method for structures based on their constant micro-vibrations.

2. A method for diagnosing and evaluating a structure based on the ambient tremors of a structure, according to claim 1, comprising dividing the continuously measured ambient tremor time history, extracting a plurality of partial time histories, calculating the expected value of the index for each partial time history, and using the sample average thereof as the estimated value of the index.

3. The method for diagnosing and evaluating a structure based on ambient microtremors of the structure according to claim 2, wherein the duration of the partial time history is 1 to 2 minutes.

4. The method for diagnosing and evaluating a structure based on ambient microtremors, according to claim 1, wherein the aforementioned observations are performed after the construction of the structure, before and after renovation work, and during periodic inspections, and the estimated values ​​at each observation point are compared with each other to diagnose and evaluate at least one of the changes over time among the seismic performance of the structure, the risk of collapse during a major earthquake, the continuity of use, and the changes before and after renovation work.

Images